Three-dimensional force input control device and fabrication

• US 8,053,267 B2
• Filed: 08/06/2010
• Issued: 11/08/2011
• Est. Priority Date: 12/29/2003
• Status: Active Grant

• Current Assignee: Vladimir Vaganov
• Original Assignee: Vladimir Vaganov
• Inventors: Vaganov, Vladimir
• Primary Examiner(s): Roman; Angel
• Application Number:
  US12/852,419
• Publication Number:
  US 20100317139A1
• Time in Patent Office: 459 Days
• Field of Search: 438/48, 438/50, 438/53, 257/E21.001, 257/E21.211
• US Class Current: 438/53
• CPC Class Codes: G01L 1/044 of leaf springs
• CPC Class Codes: G01L 5/162 of piezoresistors
• CPC Class Codes: G01L 5/223 to joystick controls
• CPC Class Codes: G06F 3/0338 with detection of limited linear or angular displacement of an operating part of the device from a neutral position, e.g. isotonic or isometric joysticks
• CPC Class Codes: H01L 21/30 Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 manufacture of electrodes thereon H01L21/28
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/10158 at the passive surface
• CPC Class Codes: H01L 2924/181 Encapsulation

Abstract

The present invention provides three-dimensional force input control devices for use in sensing vector forces and converting them into electronic signals for processing, and methods of fabricating three-dimensional force input control devices for sensing vector forces and converting them into electronic signals for processing. In some embodiments, methods of fabricating provide a semiconductor substrate having a side one and a side two; fabricate stress-sensitive IC components and signal processing IC on side one of the substrate; fabricate closed trenches on side two of the substrate, the trenches forming boundaries defining elastic elements, frame areas, and rigid islands, and remove additional substrate material from side two of the substrate in the frame area leaving the dimension of the rigid island protruding outward from side two.

Claims

1. A method of fabricating a three-dimensional force input control device for sensing vector forces and converting them into electronic signals for processing on a single substrate, the method comprises the steps of:

providing a semiconductor substrate having a side one and a side two;

fabricating stress-sensitive integrated circuit (IC) components and signal processing IC on the side one of the substrate;

fabricating closed trenches on the side two of the substrate, the trenches forming boundaries defining elastic elements, frame areas, and rigid islands, and

removing additional substrate material from the side two of the substrate in the frame areas leaving the dimension of the rigid islands protruding outward from the side two and larger than the remaining thickness dimension of the frame area minus a thickness of the elastic element,

whereby the rigid island extends out from the substrate.

2. The method of claim 1, wherein the step of removing part of the substrate from the frame areas on the side two is done by the process selected from the group consisting of:

selective etching, mechanical cutting, laser cutting and combination.

3. The method of claim 1, wherein the step of fabricating the closed trenches on the side two of the substrate further comprising the steps of:

depositing protective masking layer on the side two of the substrate;

photolithographically defining a pattern of the rigid islands, the elastic elements and the frame areas;

removing masking layer from elastic element areas, and

etching substrate from the side two of the elastic element areas to a selected thickness.

4. The method of claim 1, wherein the steps of fabricating closed trenches on the side two of the substrate and the step of removing part of the substrate from the side two of the substrate from the frame areas further comprising the steps of:

depositing at least one protective masking layer on the side two of the substrate;

photolithographically defining the pattern of the rigid islands, the elastic elements and frame areas on the substrate;

removing the masking layer from elastic element areas;

etching substrate from the side two at the elastic elements to a depth dimension between a final thickness of the frame and a final thickness of the elastic elements, through the at least one protective masking layer on the rigid islands and the frame areas;

removing the masking layer from the frame areas, and

etching the side two of the substrate at the elastic elements and the frame areas to the final thickness of the elastic elements.

5. The method of claim 1, wherein the step of fabricating closed trenches on the side two of the substrate and the step of removing some of the substrate from the side two in the frame elements further comprises the steps of:

depositing a first protective masking layer on the substrate;

photolithographically defining and protecting a pattern of the rigid islands;

removing the first protective masking layer from areas at the elastic elements;

depositing a second protective masking layer on the substrate;

photolithographically defining a pattern of the elastic elements;

removing the second protective masking layer from the elastic elements;

etching the elastic elements from the side two of the substrate to a certain depth;

removing the second protective masking layer from the frame elements, and

etching the elastic elements and the frame elements from the side two of the substrate to a selected thickness of the elastic elements.

6. The method of claim 1, wherein the step of fabricating the closed trenches on the side two of the substrate comprises fabricating the closed trenches on the side two of the substrate within each of a plurality of dice areas, and wherein the fabricating the closed trenches on the side two of the substrate within each of the plurality of dice areas and the step of removing the additional substrate material from the side two of the substrate in the frame areas further comprises the steps of:

depositing a first protective masking layer on the substrate;

photolithography defining a pattern of the rigid islands, the elastic elements and the frame elements;

removing the first protective masking layer from the elastic elements;

etching the elastic elements to a selected thickness;

depositing a second protective masking layer on the substrate including over the closed trenches and the elastic elements;

removing the second protective masking layer from the frame elements, and

etching the substrate at the frame elements to a selected thickness.

7. The method of claim 1, wherein the steps of fabricating the closed trenches on the side two of the substrate and the step of removing additional substrate material from the side two of the substrate in the frame areas further comprise the steps of:

depositing a first protective masking layer on the substrate;

depositing a second protective masking layer on the substrate having etching rate selectivity to the first masking layer;

photolithographically defining a pattern of the rigid islands on the second protective masking layer;

removing the second protective masking layer from the elastic elements and the frame areas;

photolithographically defining a pattern for the elastic elements and the frame areas on the first protective masking layer;

removing the first protective masking layer from the elastic elements;

etching the substrate from the side two at the elastic elements to a selected thickness;

removing the first protective masking layer from the frame areas leaving the second protective masking layer on the rigid island elements;

etching at the elastic elements and the frame areas from the side two of the substrate to pre-selected thickness of the elastic elements.

8. The method of claim 1, wherein the step of fabricating closed trenches on the side two of the substrate and the step of removing the additional substrate material from the side two of the substrate in the frame areas further comprise the steps of:

depositing the protective masking layer on the substrate;

photolithographically defining a pattern of the rigid island elements on the protective masking layer;

photolithographically defining a pattern of the elastic elements and frame areas;

etching substrate from the side two in the elastic elements to a depth dimension of a difference between a final thickness of the frame areas and a thickness of the elastic elements through the protective masking layer on the rigid island elements and a photoresist layer on the frame areas;

removing the photoresist layer from the frames areas;

etching substrate from the side two at the elastic elements and the frame areas to selected thickness of the elastic elements.

9. The method of claim 1, further comprising separating dice from the semiconductor substrate, comprising:

depositing a protective masking layer on the side two of the substrate;

photolithographically defining a pattern of the rigid islands on the protective masking layer;

photolithographically defining a pattern of the elastic elements, the frame areas and separating dice trenches;

etching substrate from the side two in the elastic elements and the separating dice trenches to a selected thickness using protection from the protective masking layer on the rigid islands and a photoresist layer on the frame elements from the etching;

removing the photoresist layer from the frame areas, and

etching substrate from the side two in the elastic elements, the frame areas and the separating dice trenches to a pre-determined thickness of the elastic elements.

10. The method of claim 1, further comprising the steps of:

aligning an additional machined substrate with the semiconductor substrate;

bonding the semiconductor substrate to the additional machined substrate providing bonded substrates; and

dicing the bonded substrates into individual dice.

11. The method of claim 10, further comprising the step of;

placing springy shell elements on the rigid islands.

12. The method of claim 10, further comprising the steps of:

depositing plastic material on a surface of the bonded substrates such that the plastic material is adapted to form external force transferring elements; and

shaping the plastic material on the surface of the bonded substrates to one or more selected shapes in a batch fabricating process.

13. The method of claim 10, further comprising the steps of:

positioning individual dice on an additional substrate with a selected pitch;

depositing plastic material on the surface of the additional substrate for forming external force transferring elements;

shaping the plastic material on the surface of the additional substrate to a selected shape, and

separating individual dice from the additional substrate to form devices.

14. The method of claim 1, wherein the removing the additional substrate material from the side two of the substrate in the frame areas further comprises removing the additional substrate material from the side two such that the rigid island elements extend out from the substrate and are adapted to couple with an external force transferring element or receive external mechanical forces.

15. The method of claim 1, wherein the fabricating the elastic elements comprises, for each elastic element, fabricating an elastic flat element coupled with a corresponding rigid island and extending to a corresponding frame area such that the corresponding frame area couples with at least part of a periphery of the elastic flat element.

16. The method of claim 15, wherein the fabricating, for each elastic element, the elastic flat element comprises fabricating the elastic flat element such that one or more of the stress-sensitive IC components are in the elastic element.

17. The method of claim 15, wherein the fabricating, for each elastic element, the elastic flat element comprises fabricating the elastic flat element such that three or more of the stress-sensitive IC components are in the elastic element.

18. A method of fabricating a three-dimensional force input control device for sensing vector forces and converting them into electronic signals for processing, the method comprises the steps of:

providing a semiconductor substrate having a side one and a side two;

fabricating a plurality of sensor dice from the semiconductor substrate, comprising;

fabricating at least one stress-sensitive integrated circuit (IC) component and signal processing integrated circuits on the side one of the substrate;

fabricating, within each sensor die, a closed trench, an elastic element, frame area, and rigid island on the side two of the substrate; and

removing, within each sensor die, additional substrate material from the side two of the substrate in the frame area leaving the dimension of the rigid island protruding outward from the side two and larger than the remaining thickness dimension of the frame area minus a thickness of the elastic element,

whereby the rigid island extends out from the substrate.

19. The method of claim 18, further comprising:

fabricating a plurality of separating dice trenches between each of the plurality of sensor dice.

20. The method of claim 18, wherein the fabricating, within each sensor die, the closed trench, the elastic element, the frame area, and the rigid island, comprises:

fabricating the elastic element within the semiconductor substrate such that at least three stress-sensitive IC components are located in the elastic element;

fabricating the frame area formed around the elastic element and coupled with at least part of a periphery of the elastic element; and

fabricating the rigid island such that the rigid island is coupled with the elastic element and is configured to transfer an external vector force to the elastic element and through to the stress-sensitive IC components.